The present invention relates generally to image rendering systems, and, more particularly, the invention relates to zoom control within image printing systems.
Image printing systems such as printers for use as computer peripherals often are require to zoom in or out on an image. Zooming in on the image creates an enlarged image or an enlarged area of the image. Zooming out creates a reduced image.
Computer software venders and printer manufacturers have created a vast array or application level software and peripheral hardware to achieve these task but each suffers from one or more problems.
Application level computer applications, for example, require that the image be loaded into a computer where it is manipulated. The loading is accomplished by scanning an image from a printed medium, photographing an image with an electronic camera or various other methods. The manipulation for zooming is then program dependent but generally requires the computer to execute a mathematical algorithm to interpolate pixels thereby altering data.
A problem that arises by manipulating the data in this way is that the mathematical interpolations, while often creating images satisfactory to the eye, are not true renderings of the image. An intermediate zoom such as 1.5:1 creating a one hundred fifty percent enlargement will interpolate intermediate pixels by averaging tile boarder pixels, or by performing other mathematical operations which create intermediate blendings. This reduces image sharpness and therefore reduces image quality. Another problem that arises in these systems is aliasing. Aliasing distorts the image by taking an original digital signal which is then quantized to create an analog signal. The analog signal is then resampled at intervals representative of a degree of enlargement or reduction required. The resampling often misses highs and lows of the original signal and loses data as a result. These losses are known as aliasing.
These applications command the computer to perform various tasks via a rigid instruction set for the family of microprocessors within the computer. As such, the software is processor speed dependent. Further, the final product must then be downloaded to the printer thus adding further delay to the system.
Accordingly, it is an object of this invention to provide a zooming system which creates an enhanced, quality rendering of the image.
It is another object of this invention to provide a zooming system which reduces a need for mathematical interpolation between pixels. It is still another object or the invention to provide a zooming system which reduces aliasing among pixels thereby reducing image noise.
It is a further object of the invention to provide a zooming system which will increase processing speed by executing within the printer thus producing a zoomed image faster
These and other objects of the invention will be obvious and will appear hereinafter.